Analysis of acoustic emission signals during bending deformation of magnesium alloy sheet

Acoustic emission (AE) refers to an elastic wave occurring during plastic deformation and fracture. In this work, AE techniques were utilised to investigate the characteristics of bending deformation of magnesium alloy sheets (AZ31B). In the experiments, AZ31B sheets with thicknesses of 1 mm and 3 mm were examined. During bending deformation, a significant number of AE signals were generated in the initial stage when plastic deformation. Subsequently, the occurrence of AE signals decreased. The plastic deformation characteristics and the number of AE hit counts were analysed. In the bending process, complete material fracture does not occur instantaneously; instead, cracks propagate progressively as bending advances, generating signals with short durations. AE signals produced at the point of fracture are characterised by short durations. Furthermore, the AE characteristics were analysed based on the presence or absence of lubrication. When proper lubrication was applied, the total hit count of AE signals was significantly reduced. Signals with long durations, low peak amplitudes, and low energy were predominantly minimized. This analysis provided insights into the characteristics of AE signals generated by friction. By examining the AE characteristics during bending deformation, the features of AE signals associated with the bending and fracture of magnesium alloy sheets were identified.